Override Message-ID by configuration

Question

When I send email from my application using the default WildFly mail session, the auto-generated message ID gives away that my server is WildFly:

Message-ID: <[e-mail]>

For security reasons, I'd like to suppress or override the wildfly substring in the message ID.

Is there a configuration element or a system property to do that?

Answer 1

Upgrade to JavaMail 1.5.3. That official release has Bug 6496 -Message-Id leaks current user/hostname of the Java process marked as resolved.

Otherwise, the Message-ID computation uses the InternetAddress.getLocalAddress method which is including the username. You can set the mail.from session property to override including the O/S user name.

public static void main(String[] args) throws Exception {
        Properties props = new Properties();
        props.put("mail.from", "[e-mail]");
        Session s = Session.getInstance(props);
        MimeMessage m = new MimeMessage(s);
        m.addFrom(InternetAddress.parse("[e-mail]"));
        m.setText("");
        m.saveChanges();
        m.writeTo(System.out);
}

Which will output something like:

From: [e-mail]
Message-ID: <[e-mail]>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

If you are using the default session you can just add 'mail.from' to the system properties.

Answer 2

Answering my own question: The wildfly part of the message ID corresponds to the value of the user.name system property. My server happens to be running under a Linux user account named wildfly.

So one option would be to use a different user account. Alternatively, simply passing -Duser.name=foo to the WildFly start script is enough to change the message ID.